Why is House seeing Amber? Is she dead right?

Yes, Amber is dead. House is hallucinating her presence. I believe it has something to do with her death being partially his fault.

No tumor though

i really hope he doesn't, that would be such a rip off

House's subconscious mind sees Amber as      purplepen82 đã đưa ý kiến it's a guilt trip because I'd say he's a lot thêm just being partially at fault in her death it was 100% his fault. Just my opinion.
A tumor would not only have been a rip off from Grey's Anatomy, but it's what has happened in the season finale Bones with Booth as well.
Anne Dudek Is having a baby.

No tumor. He's hallucinating because of the vicodin. He sees Amber (and once Kutner) because he feels guilty about their deaths, as mentioned before.

Yes shes dead because when house got drunk he called willson and amber picked up the phone.She came to get house and they got on the bus and a dump truck hit the bus,putting amber in a coma at first.then house trys to sacrafice his brain to save her for willson.Then wen house is on a white bus with amber she tells his that only one of them could go back and that he is going to go back and he does.willson has a breakdown and leaves for a few months.and no,no tumor,its the vicaden

Amber is 100% dead. He's seeing her because he blames himself for Kutner's death, because he didn't see it coming. This stirred his old guilt about Amber's death. Basically, he's going crazy.